Methods for the production of polyolefins with end-functionalized groups are typically multi-step processes that often create unwanted by-products and waste of reactants and energy. For reviews of methods to form end-functionalized polyolefins, see: (a) S. B. Amin and T. J. Marks, Angewandte Chemie, International Edition, 2008, 47, pp. 2006-2025; (b) T. C. Chung Prog. Polym. Sci. 2002, 27, pp. 39-85; (c) R. G. Lopez, F. D'Agosto, C. Boisson Prog. Polym. Sci. 2007, 32, pp. 419-454. A process with a reduced number of steps, even one step, would be desirable.
U.S. Pat. No. 4,110,377 discloses secondary aliphatic amines alkylated with alpha-olefins, such as ethylene, propylene, hexene, and undecene. Likewise, several literature references disclose hydroaminoalkylation of olefins using various catalysts (see J. Am. Chem. Soc. 2008, 130, pp. 14940-14941; J. Am. Chem. Soc. 2007, 129, pp. 6690-6691; Angew. Chem. Int. Ed. 2009, 48, pp. 8361-8365; Angewandte Chemie, International Edition, 2009, 48, pp. 4892-4894; Yuki Gosei Kagaku Kyokaishi (2009), 67(8), pp. 843-844; Angewandte Chemie, International Edition (2009), 48(6), pp. 1153-1156; Tetrahedron Letters (2003), 44(8), pp. 1679-1683; Synthesis (1980), (4), pp. 305-306). Corey discloses low molecular weight olefins treated with hydrosilanes in the presence of Cp2MCl2 and n-BuLi to prepare low molecular weight hydrosilylated products.
None of the above references however disclose functionalization of polyolefins, particularly polyolefins having Mn's over 500 g/mol having large amounts of vinyl terminal groups.
U.S. Pat. No. 8,399,725 discloses certain vinyl terminated polymers that are functionalized, optionally, for use in lubricant applications.
U.S. Pat. No. 8,372,930 discloses certain vinyl terminated polymers that are functionalized in U.S. Pat. No. 8,399,725.
U.S. Pat. No. 8,283,419 discloses a process to functionalize propylene homo- or copolymer comprising contacting an alkene metathesis catalyst with a heteroatom containing alkene and a propylene homo- or copolymer having terminal unsaturation.
Additional references of interest include U.S. Pat. Nos. 6,111,027; 7,183,359; 6,100,224; and 5,616,153.
Thus, there is a need to develop a means to provide functionalized polyolefins (particularly end-functionalized) by efficient reactions, particularly reactions with good conversion, preferably under mild reaction conditions with a minimal number of steps, preferably one or two steps. The instant invention's use of Lewis and Bronsted acid catalysts to introduce aromatic groups is both a commercially economical and an “atom-economical” route to end-functionalized polyolefins.
End-functionalized polyolefins that feature a chemically reactive or polar end group are of interest for use in a broad range of applications as compatibilizers, tie-layer modifiers, surfactants, adhesives, and surface modifiers. Herein is described a novel method for their production by the reaction of vinyl-terminated polyolefins with aromatics in the presence of an acid catalyst. This method is useful for a range of vinyl terminated polyolefins, including isotactic polypropylene (iPP), atactic polypropylene (aPP), ethylene propylene copolymer (EP), polyethylene (PE), and particularly propylene copolymers with larger alpha-olefin comonomers such as butene, hexene octene, etc. The vinyl terminated polyolefin useful herein can be linear or branched.